Field of the Invention
This invention relates to 2-up coming and going methods of bookmaking. The term "book" is used herein in a broad sense to mean any assembly of pages arranged in a required order and includes not only printed books in the normal sense but, for example, diaries and any collection of printed sheets arranged in a required order.
Bookmaking using the 2-up coming and going method involves making two books or book sections at once from a paper web which has been printed so that each successive length of the web shows a number of pages each of which appears only once, the pages being printed in such positions that after slitting, cutting, if necessary folding, and collating a half block is formed which has two side-by-side sequences of pages. This half-block contains all the pages, hereinafter referred to as the primary pages, of the book or book section which have been printed on the web. Each side of each leaf of the half-block shows two pages arranged head-to-head or tail-to-tail, one page being from one sequence and the other page being from the other sequence. Each sequence contains half the primary pages of the book or section, one sequence containing the primary pages of the first half of the book or section in proper order and the other sequence containing the primary pages of the second half of the book or section in proper order. If one considers the order of the primary pages in each sequence with respect to one face of the half-block then the primary pages in one sequence "go" from that face while the primary pages in the other sequence "come" to that face.
In addition to the primary pages the half-block may also include secondary or inserted pages such as drawings, photographs or title pages which are not printed in the same operation as the printing of the web referred to above. These inserted pages may, for example, be fed into the half-block during collating. Alternatively, the inserted pages may be grouped together in a separately printed insert section which may be fed between two half-blocks when the half-blocks are combined to form a block as described below, may be added to one of the half-blocks before the half-blocks are combined, or may be fed onto the top or bottom of the block after the half-blocks have been combined.
A book consisting of, for example, 192 primary pages, may be made by arranging one face of each half-block to show pages 1 and 192 while the leaf at the opposite face of each half-block will show pages 96 and 97. Pages 1 to 96 will in each half-block go from the one face to the other and pages 97 to 192 of that half-block will come to that face from the other face.
A block is then made by the imposition of one half-block on another identical half-block which is reversed in position relative to the one half-block so that the block thus formed can be separated into two books each of which will have all the required primary pages.
Thus in the example given above, the faces of the two half-blocks which show pages 96 and 97 would be juxtaposed with page 96 of each half-block opposite page 97 of the other half-block.
As previously indicated, two book sections can also be made at once using the 2-up coming and going method described above. In this instance a block will be formed which is a double book section and which can be separated into two book sections each of which will have all the required pages.
The above double book section can be combined, prior to separation, with other sections of the book printed using the 2-up coming and going method to produce a larger block which can be separated into two complete books.
The half-blocks referred to above will be made up from sheets or signatures, hereinafter referred to as "book elements".